Improvement in steam-engines



UNITED STATES GEORGE I. VVASHBURN, 0F WORCESTER, MASSACHUSETTS.

IMPROVEMENT IN STEAM-ENGINES.

Specification forming part of Letters Patent N0. 49,809, (lated September 5, 1865.

To all whom it may concern Beit known that I, GEORGE I. WAsHBURN, of the city and county of NVorcester, and State ot' Massachusetts, have made certain new and useful Improvements in Steam-Engines; and I do hereby declare the following to be a clear and exact description ot the. same, reference being had to the accompanying drawings, which are made part of this speciiication, and in which-- Figure l is a vertical longitudinal sectional viewof a single cylinder engine, which is shown as attached by its piston-rod and loop to the wiist on the disk which is attached to the main shat't. Fig. 2 is a transverse vertical section in the line mx, Fig. 1. Fig. 3 is avertical longitudinal section of a single-cylinder engine in which the pistou-packing is fast to the cylinder and the ends ofthe plug form the pistonsurl'accs. The passages analogous in their action to the passages K K K2 K3, Fig. 6, are inadein the body of theplug-piston. The spaces 4 2 l 3 5 are all analogous in their action to the correspondingpartsinFig.1. Figetisaviewot' two cylinders, one high-pressure and the other low-pressure, and the latter receiving the eX- haust-stean'i from the former. Fig. 5 is ahorizontal central section ot' a combined double engine, the moving parts being shown in place. Fig. 6 is a central vertical longitudinal section on the line n: Fig. 5. Fig. 7 is a transverse vertical section on the line y y, Fig. 5, with the moving portions partly in section. Fig. 8 is a transverse vertical section on the line ze, Fig. 5. Fig. 9 shows a portion of the exhaust-pipe with its regulatin g stopcock and safety-valve. Fig. l() shows a modification ot' the stem-loop.

Similar letters refer to like parts in each ot' the figures.

The invention consists of a steam cylinder within which are located two single-acting pistons, between which, and upon the same axis or stem with the pistons, are two disks, which, although traversing the cylinder steam-tight, perform no office as pistons to receive or trans mit pressure, but serve to separate the space between the single-acting pistons into three spaces, the middle one being open to the steam from the boiler when the steam takes the direction indicated by the arrows, Fig. 6, and the outer ones being' always open to the outer air,

condenser, or place in which the exhaust-steam is utilized or applied. The steam is, by the reciprocating motion of the moving parts, alternately admitted to and exhausted from the et'- fective spaces at the ends ot' the cylinders, and this motion, and the consequent opening and closing ot'certain ports to certain passagesgnay be utilized for the purposes ot' a valve, or by connection with the stem on which the said pistons and disks are placed, or by a prolongation of the stem as a piston-rod, any desired connection with machinery may be made, as illustrated in Figs. Il, 5, and 7.

Among the principal objects to beattained is to canse the momentum of the moving parts to be overcome by the elastic pressure ot' the steam, instead of beingovercome by the tension of the materials. Another object is to make the motions ot' the valve as quick as that ef the piston by attaching it to the piston itself.

In engines of ordinary construction the crank and pin receive much of the momentum ot' the moving parts, and consequently alimitot speed is found in their power of resistance to fra-cture or displacement. ln the engine, Fig. 1, a cushion ot' live steam receives and overcomes the momentum ot' the moving parts and causes their return motion. 'Vhen the piston is at half its stroke the centers ot' the disks and the centers of the ports coincide. The steam is reversed as soon as the disks have passed these ports, and acts expansively while the disks cover the ports, and lthe point at which the steam is reversed, as well as the duration ot' the expansion, is governed by the widths of the disks and that ot' the ports taken together.

To enable one skilled in the art to which my invention appertains to make and construct my engine, I will proceed to describe it in detail, and will commence with it as illustrated in Fig. l,which is a double-acting single-cylinder engine.

4 5 are the e'ective spaces of the cylinder, which are traversed by the pistons B B', which are attached to the stem D, upon which latter' also are disks C C', which divide the space between the pistons B B into three parts, 2 l 3, so that the length ot' the cylinder is divided by the pistons and disks into tive spaces, 4c 2 l 5, et and 5 being included between the pistons and the cylinder-heads, where they consteam, making the inlet the exhaust, Sac.

stitute the effective spaces to and from which the steam is admitted and exhausted. rIhe central space, 1, is in direct communication with the boiler by means of the pipe E, and alternately in connection with the spaces 4 and 5 by means of the pipes F F', respectively, and two spaces, 2 3,'included respectively between B and C and B' and C', which spaces are always in communication with the exhaustpipes G G', and alternately in communication with the eective spaces 4 5 by means of the pipes F F', to exhaust the steam therefrom. The relative distances between the disks and pistons areinvariahle, and the passage in which they reciprocate may be of equal diameter at all points of its length, or a portion contracted,

as in Fig. 1. The disks and pistons may be simply attached to a stein, as in Fig. 1, or B and O, B' and C', may be united by enlargements, as in Fig. 5. These are points of detail; but it is understood that the spaces included between these portions maintain their relative positions, and by the motion are brought in relation with certain ports, as described, by which the flow of steam is governed and directed.

I will mention at this point that it is possible to run the engine by reversing the flow of In this case the space 1 will become the exhaust and the spaces 2 and 3, respectively, will become the steam-spaces, from which the supply of steam will pass to the ei'ective spa-ces 4 and 5 of the engine, the steam-pipes being changed so that the space 4 communicates by pipe F with the space 3 andthe pipe F' communicates between 5 and the space 2.

lThe piston-rod H is shown as connecting byv a loop, H' H', with the wrist I on the disk J, by which the reciprocating is converted to a rotary motion in a common manner.

Referring to Fig. 1, which illustrates a don-l ble acting single-cylinder engine, I will state that, taking the piston at that part of its stroke when the disks have just passed the ports M M', (and this point of the stroke will be determined by the width of the disks, takeninconnection with the width of the ports,) the livel steam from the boiler is admitted to the eli'ective space to which the piston is advancing, so as to overcome the momentum of the moving parts within the cylinder by opposing their motion, and upon the return-stroke the live steam, until the disks have covered the ports, acts effectively upon the pistons., Now, assuming that these actions of the live steam are in eEect equalpto each other, the expansive action of the steamfwhich takes place while the parts M M' are covered bythe disks, is the effective working power of the engine. This is a valuable feature in an engine which is designed to be driven at great speed under immense pressure.

In Fig. 5 is illustrated a combined engine consisting of two cylinders, Nos. 1 and 2,.each constructed in substantially the samemanner as that in Fig. l; but'the spaces 2 l 3 and disks C C', as moved by pistons B B of one cylinder, govern the action of the steam in the effective spaces ofthe other cylinder.

The function of each of the pipes or passages K K' K2 K3 is similar to that of the pipes F F' of Fig. 1 in connecting effective space with a steam-space and an exhaust-space alternately; but in the case ot' the colnbined engine each of these passages opens from an effective space in one cylinder, alternately into a steam and exhaust space in the other cylinder in such a manner that the disks C C' in one cylinder, in passing the center of their stroke, effeet the reversing of the pressure upon the pistonsin the other cylinder. To describe this operation in detail: In the cylinder No. 2, Fig. 5, effective space 4 is receiving live steam through the channel K, Fig. 6, from steamspace 1, cylinderNo. 1. Atthe same time space 5, cylinder No. 2, by means of a channel, K', Fig. 6, is opened to exhaust-space 3, cylinder No. 1. Consequently the pistons of cylinder No. 2 move in the direction of the arrow. It will be seen that disks C G',cylinder No.2, are now in the middle of their stroke and cover ports a and b of that cylinder. When, in the course of their motion, they uncover these ports steam from steam-space 1, cylinder No. 2, passing in at port b and through pipe K2, Fig. 6, emerges from port b' into eii'ective space 4, cylinder No. 1. At the same time, port a being opened to exhaust-space 2, cylinder No. 2, the effective space 5, cylinder No. 1, is opened by means of channel K3,Fig. 6, into said exhaustspace, and through passage d, across exhaustspace 2, cylinder No. 1, into exhaust-pipe e and the outer air. The channels d d' connect the exhaust-spaces 2 and 3 of each cylinder respectively at all times, so that their contents may escape by opening e c' to the open air. At this point the pistons ot' cylinder No. l commence to move in the same direction as the arrow in cylinder No. 2. When disks O C', cylinder No. 1, have passed the middle of their stroke and uncovered the ports of that cylinder corresponding to t b of cylinder No. 2, at which period the pistons in cylinder No. 2 will be ready to commence their return-stroke, the said disks will have reversed the pressure upon the pistons in cylinder No. 2, giving live steam through pipe K', Fig. 6, from steam-space 1 of cylinder No.1 to eii'ective space 5, cylinder No.2, and allow the steam to exhaust from space 4, cylinder No. 2, through pipe K, Fig. 6, into exhaust-space 2, cylinder No. 1, from which and through pipe e it proceeds into the outer air.

Although the motions described do not trace the opera-tion through a complete revolution of the main shaft, yet the succeeding operations are so strictly analogous to those already detailed that it may be readily perceived how the motions of the pistons and disks, together with the spaces 2, 1, and 3 in each cylinder, respectively, produce the desired action of the steam, wherefrom a continuous rotation of the main shafts results.

It will be observed in this connection that proportioning the width of the disks C C on each cylinder and the Widths of the ports across which they pass, and thus controlling the period during which the passa-ge leading toand from the effective space is closed, the

steam may be used expansively in one effective space of the cylinder, and at the same time act as a cushion in the otherefft'ective space ofthe same cylinder, thus opposing the momentum of the moving parts and relieving. the crank-pin ofy a strain towhich it would otherwise be ex- Y posed.

The stems D,midivay between the disks C C', are wrought into a loop, H', similar in its construction and rotation to the crank-pin to that already described in treating of,.]34ig. 1. A

- double-crank shaft provided withdisks J is located transversely to the directionof-thc motion of the pistons. The cranks are placed at an angle of ninety degrees with each other, and

possess the peculiarities and advantages of that peculiar construction. The office ot' thedisks J is to maintain thestemsand loops in such a position as not to intert'erewith the action of the crank-pin.

y Fig. 5 may be also taken as illustrative of a valve, by which steam may be alternately admitted to and exhausted from separate exterior chambers. 'Io utilize it for this purpose I may connect the said chamber or chambers with one or more passages, K K K2 K3, Fig. 6, or with either or both lot' the cylindersthemselves, by means of ports so located as to bear the same relation to the disks C C as do the portsa b, Fig. 5. This may be used with or Without the presence of the cranks and shaft,

which, although they modify the motion ot' the pistons, do not essentially alter its operation as f a valve. Whether regarded in its character as a valve or engine, it will be seen thatgwhile the moving parts of one cylinder are in the act of reversing the pressure Aupon those in the other they are themselvesunder full pressure of steam from the other cylinder, and thus at no time, however short, is the engine or valve free from eiiective steam-pressure.

The'modification shown in Fig. l0 consists o an oblique loop to the stem D, the ei'eet of Whi .h is to bring thesteam-pressure to bear upon the pistons of the combined engine, (see Fig. 5, so as' to overcome the momentum vof the pist ns when they arrive near the end of their stro e, and thus save the cranks from -\strain. '.Ilhq loop, instead of standing vertially, is inclined, so that when the crank-pin is\. in one end o\f the Vloop the mid-length of the stem is forward-mr beyond the mid-length of the cylinder, and still when the crank-pin is in the center of the loop the pistonis just where it would be were the\loop notinclined. So Ythe only effect of making the loop inclined is to cause thehpiston to reach and pass the ports marked a, b in Fig. 5y before the crank has reached its vertical position, and hence before the other piston has arrived at the end of its stroke. Thelloop must be soshapedthat each" endof it,when oecupie'dby the crank-pin, shall tbe, nearer the rear than the frontend of its stem,

thedirection ot' the motion ofthe stem'detervvmining which is the front end. The piston, by

this device, may be made to fly from steampressure to steam-pressure, While the crank has only to drive the machinery. i

The back-pressure valve Ois placed over or within the exhaust portor pipe, to which the exhaust-pipes of the engine converge for the purpose ot' stopping the action of the engine .withoutallowing the cylinder to become emptied ot' steam, which is ordinarily the case Vwhen the exhaust is left open and the engine stopped by shutting oft' the steam. I propose to stop the engine by closing the exhaust-opting ing. by means of stop-cock p, Fig. 9, which has the effect of causing the exhaust-steam to accumulate, and by its increasing pressure to oppose the motion of the piston. The backpressure may be allowed to accumulate to any extent desired, and is kept Within the proper loft' the steam, asdescribed, andyield to the steam when it has attained the determinate pressure, thus performing both functions.

In the ordinary method ot' stopping an engine by shutting otf the supply of steam the machine is brought to rest by the. friction ot' the running parts, and during the interval between the shutting ott' of the steam and the stopping of the machinery those parts which operate within the cylinder in the case of my engine, Fig. 5, being nearly all of the moving portions, are apt to becomedry and to cut the friction-surfaces. By means of this retention of steam the moving parts are surrounded by steam at all times, While the exigirle can be more expeditiously stopped, as well as completely controlled, by means of the said backpressure.

The difficulties above alluded to are especially apparent in the case oflocomotives which shut o the steam while the piston has yet to make a considerable number of revolutions before the stoppage of the engine.

The double-engine shown in Fig. 5 may be utilized by allowing thecrank-shaft to project oniboth sides, placing driving-Wheels directly upon it, the cylinder being placed under the boiler, and thus securing a locomotive-en gine of great simplicity.

In connectionV with the above I propose to prolong the piston-rods through the heads ot' the cylinders and attach pump-pistons thereto,A 1 z which reciprocate in pump-cylinders, so as totv make a locomotive steam lire-engine, suitable apparatus being applied to disconnect the wheels from the crank-shaft when required. For stationary purposes the projection of the said piston-rod may afford the means of operating pumps, hammers, stamps, molds, blowers, Snc., either with or without utilizing the rotation of the cran k-axis, to the directpurpose of driving additional machinery by pulleys and band or otherwise.

The device the subject of this specification, in its various suitable modications, may be used as an engine, a valve, or a meter for fluids of any kind, and, owing to the location of the working parts within the cylinder, less attention is required in the way of lubricating by an attendant and less danger is incurred by the lack of said attention.

I desire to state that my invention is susceptible of several modifications which will be found on examination to embrace the same general principles and to bear a relationship which is nearer than is apparent at iirst sight.

By referring to the main feature of my invention, as stated in the preliminary syllabus ofinvention near the commencement of this specilication, it will be seen that the essential feature depends upon the arrangement and common action of the pistons and disks which divide the length of the cylinder into spaces, which are brought into certain relation to openings or ports in the cylinder to produce the result which I will not again detail, as it has been already described.

Among the modifications may be found the following:

First. The cylinder may be the moving part, while the pistons are xed. The re-arrangement would require certain modification of detail sufficiently obvious to an expert.

Second. Inasmueh as the pistons B B do not pass over ports, elastic diaphragms attached to the inner periphery of the cylinder and to the piston-rod may be substituted for the pistons, and the packing-rings of the two cylinders, as well as those ot' the two disks, may be made fast to the cylinder, as in Fig. the piston itself in thiscase containing the channels m m for the steam, analogous in their functions to the channels F F in Fig. l.

Third. Referring' to Figs. l and 5 of the drawings, which illustrate the single cylinder and a combined engine, the inlet and eX- vhaust ports may be reversed in their action,

" gine may be placed near eachother or in separate rooms. They may be attached to a common shaft or to separate main shafts running at separate speeds and driving distinct machinery.

Fifth. They may be placed at an angle with each other when attached to the same shaft. Sixth. An adjustable cut-off valve may be placed in the steam-pipe E, or two separate ones may be placed in the Asteam-passages F F', Fig. l, and K Kl K2 K3, Fig. 5, 'at which latter points the valves would be nearer their work.

Seventh. Inasmuch as the steam-space of one cylinder supplies the effective spaces of the opposite cylinder when the engine is in motion,'I may reverse its motion-that is to say, rotate the main shaft in a contrary direction by changing the flow of steam, so that the steam which flowed from the steam-space of one cylinder to a certain end or effective space of the other cylinder shall flow to the opposite end of the last-mentioned cylinder. The expedients by which this may he accomplished are various, and Iwill suggest one. which consists in placing a cock or double D-valve in a point of junction between the pipes K K K2 K3, Fig. 6, so that by its motion the steam may be caused to tlow in the required direction.

Eighth. Thecoactivcconnection represented in Fig. 5 may be maintained between any number of cylinders, the valve in cach cylinder governing the motion of the piston in another, or the exhaust-steam from one cylinder may be made to act as effective in another, (see Fig. 4,) and the second cylinder may be low-pressure condensing.

Ninth. ln cases of the very great pressure and high speed which I expect to obtain and use, the steam may leave the cylinder at such a pressure that it can be economically applied in a second high-pressure cylinder, and thus a series of two, three, or more cylinders be found economical; audit should be remarked that the last cylinder, should it be a low-pressure and in connection with the condenser, obtains most of its power from the atmospheric pressure, and as the high-pressure cylinder delivers the steam/ to the last cylinder, at an effective pressure 1t'.

inder, and therefore a long conn ,ctingpipe I/ does not detract from the eftieien/g ot' the apparatus. f

Having thus described my invention, the following is what I claim as neutherein and desire to secure by Letters Pat/cnt l, v

1. The combination of the pistons B B and disks G C', attached to a stem,'D, witha cylinder provided with ports whi Ih open into the spaces between and beyond t. e disks and pistons, in the manner and for the purpose described.

2. Oom binin g two or more such cylinders by means of connecting-passages, through which live steam or other iluid under'pressureis supplied from one cylinder to another, making the disks G C', which are located between the pis tons of one cylinder, act as a valve to the other cylinder or cylinders, wheth er the described apparatus be used as an engine or a valve.

3. Arranging a valve which gives steam to the effective spaces between the pistons and upon the same stem with them.

et. Arranging avalve which' connects the effective spaces with the exhaust-pipe between the pistons and upon the same stems with them.

5. In combination with the said pistons B B', disks C C', and stem D, arranging the crank ofthe main shaft within the steam or exhaust space of the cylinder.

6. The arrangement of the valves for determining the extent of the expansive action by proportioning the width of the disks and ports as described.

7. Imprisoning a body of steam of not over a determinate pressure within the cylinder for the purpose described by means of closing the exhaust, as described.

S. So arranging the loop on the piston-stem or its equivalent as to cause the piston to pass the mid-length of its cylinder before its crank' has reached its midway or vertical position.

To the above specification of my improvement in valve and steam-engine I have signed my hand this 25th of March, 1865.

GEO. l. VASHBURN. W'itnesses:

EDWARD H. KNIGHT, CHARLES D. SMITH. 

